I was refering to the coin cell that some motherboards have for keeping bios
settings between reboots.
The OP mentioned that removing the BIOS battery for a few minutes helps the
PC start so maybe it just gives the battery enough time to recover enough
charge for the reboot. Just a guess.

This means battery is having charge but removing it is causing BIOS to
reset to defaults. So is not likely problem.
Waiting an hour resolves this problem. Which means battery is not good
and waiting and hour resets BIOS (I am contradicting myself)
But why would running the client load BIOS with some useless settings
that go away when BIOS resets?
Hmmm wish I could contribute more....

Me too! I just remember reading that a dead, or dying, BIOS Battery can
lead to trouble getting the PC to POST, why I don't know. If you can
get your hands on another battery to test this it might be cheaper than
a new PSU :)